The topographical distribution of epileptic spikes in juvenile myoclonic epilepsy with and without photosensitivity

Abstract

The topographical distribution of epileptic spikes in juvenile myoclonic epilepsy with and without photosensitivity, Clinical Neurophysiology (2016), doi: http://dx.doi.org/10. 1016/j.clinph.2016.10.098 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractObjective: Up to 30% of people with juvenile myoclonic epilepsy (JME) have photoparoxysmal responses (PPR). Recent studies report on structural and pathophysiological differences between people with JME with (JME+PPR) and without PPR (JME-PPR). We investigated whether electrophysiological features outside photic stimulation differ between these subtypes. Methods:We analysed EEG recordings of people with JME at a tertiary epilepsy centre and an academic hospital. Photosensitivity was assessed in a drug-naïve condition. We compared the occurrence and involvement of posterior electrodes for focal abnormalities and generalised spikewave activity in the EEG outside photic stimulation between JME+PPR and JME-PPR. Results:We included EEG recordings of 18 people with JME+PPR and 21 with JME-PPR. People with JME-PPR had less focal abnormalities in the posterior brain regions than people with JME+PPR (19% vs 55%, p<0.05). There was no difference in the distribution of generalised spike-wave activity between people with JME+PPR and JME-PPR. Conclusion:This study demonstrates electrophysiological correlates of the previously described structural and physiological differences between JME+PPR and JME-PPR.Significance: Findings support the hypothesis that posterior interictal EEG abnormalities reflect localised cortical hyperexcitability, which makes patients with JME more sensitive to photic stimuli.

Juvenile myoclonic epilepsy as a spectrum disorder: A focused review

“…the appearance of spike-and-wave (SW) discharges in the EEG. These SW discharges showed more often a posterior predominance when compared to cases without PPR in JME [27], indicating a probable difference in neural networks. Moreover, clinical photosensitivity (seizures triggered by environmental light sources) and PPR are not completely congruent in our clinical experience [28].…”